Air-compressor.



W. BRELLWITZ.

AIR COMPRESSOR.

APPLIUATION FILED APR.1B, 1906.

Patented Mar. 28, 1911.

5 SHEETS-SHEET 1Y M'hefn'f lW. PRBLLWITZ.

AIR COMPRESSOR.

APPLICATION HLBD APR. 1s, 1906.

Patented Mar. 28, 1911.

5 SHEETS-SHEET 2.

W. PRELLWITZ.

AIR COMPRBSSQR.

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hilf/125i:

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W. P'RELLWITZ.

A1B. UOMPRESSOR.

APPLICATION HLBD 11211.19, 1996.

Patented Mar. 28, 1911 5 SHEETS-SHEET 4.

W. PRELLWITZ.

AIB. COMPRESSOR.

YAPPLICATION FILED AYE. 18, 1906.

Patented Mar. 2s, 1911.

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,l UNTE-D STATES PATENT ermee.

WILLIAM PRELLWTTZ, on EASTON-PENNSYLVANIA, Assieme To INGERSOTLRAND@aM-mmf, or NEW YORK, N. Y., A cRPoRATxoN or New JERSEY:

Anwivrrmsso.

of Euston, in the' county -of Nerthmnpton 'aalnd .State etPennsylvania,have invented new and useful IInp1.-'0Ven^1eut inAir-(Ionipressol's, O'Whieh thciullowing :i speech In ay compound nir'compresser in which un automatic choking controller' 1s used 0n thelowpressure cylinder, it has been found.

milie of that. When theehoking vulve begins to. close the intake tn thelow pressure Cylinder, the low preSSure cylinder vStarte to 'pull nYzuuui'n. the yaeulun becoming;` greater theI uiore the intake 'opening'is reduced. Then less iil; ie'furnished by the low preesure cylinderthan the capacity of the high pressure'cylinder., the high pressurecylinder will :ilse Start to pull a. vacuum.,

The object of this pressent invention 1s to fnfovide means for absolutelT reveiitiiur n vacuum in the high pressure cylinder,v which meansCompriees a hypes vulve-iii eugh. end

eff the. high. pressure cylinder cenneted by a port, which port is atall times in open .coniinunieation With'the intercolenof the compressor.y

In the accompanyingdrawings, Figure l represents a power driven compound2131.' Compressor inl top plan with my improve nient applied therete,Fig. 2 is a Side View 'of the same, Fig, 3. is sin end View, Fig.

fi. i5 .a detail Vertical` centrzilsectien through .the automatic.choking controller for-,the inthe 10W pressure pyrl'indel-r. the cholo.y .QIJX:, 4? is' a,- flet'll efr'l in .the plane' etheline .Arabe O fFig.` 4f loQliiingin the. direction'of the..

.ingl e., enig Shown,v

rse seetion threugh im L ij-eoeler. 3, driving e0 @tiene Bend 6 withSpecification of Letters Batent. Appl-mation led April 18,1906. Seria1No. 312,301-.

ffron. and had; oA lfme pistn 36 are con? eompresser shown t.' Surecylinder' l` low'- I Patented Mar.- 28', 15911.

the pistons ot the high and low pressure cylinders l und 2,respectively, and the heltdi'iven pulley 7 for th said drive shaft TheSub-liaise et the eeuipreesor'is denoted by S. The intake is denoted hyl), its pipe by l() which leads through the choking wlw '1.1. to theinlet pipe 12 of the low pressure cylinder. A pipelf lende 'from the 10Wpressure cylinder' te ene end of the intercnoler 3* and the inlet pipe1.1i, 15, for the high ).iressure. cylinder lends from the other end of'the' interceoler.v The Outlet pipe 1G, 17, of the high pressure'cylinder leads t0 any suitable compressed nir receiver not, shownherein.

The choking yali'e using 1S of the auf tonizltie Choking Controller forthe. low pres- Sure (.ylinder is 'interposed between the pipee 10 undl2, which casing is S0 arranged that a double Choking valve lll i'nay beused. The stem of the valve 11 is denoted hy 19 und it extend-sw*`upwardly-through the top 20 of thev casing 18 where it. is attached tothe 4weighted lever :21 thrugh u linkI Q2. This lerer 21' is pivoted at.23 in a bracket 24uprisinv from the' tol 20" of' the Valve easing. T lieouter end this lever is provided with Weights 25.

An auxiliary spring pressure isA exerted tending to open the chokingvalve `i'vhicli pressure .comprises a. @eil spring 2G interposedbet-Ween a shoulder 27 o n-a-n upward extension 28 0f the-piston rod anda Socket piece. 29 uprising fromfthe top20 ef tl1e. fe 11p-er e'nefthe.piston red `d3ifti"`gv-in9veinei1l in'fa, tu: g 1d in theL trip of' the[socket An agir cylinder 31 is provided with a 325 the rod 33 of.whiehis attached 'hr2/1 ebeow the-pi iv piston the la" rse' ,Mid fidirapidly,` the.. Wniidf cause. tool sudd en a .e fiar the compres/ser.Tio

A'neeteflthrough ports. 38.339, cont-rolled by a manually operatedneedle vail-ve 40 so that .the speed fifth-e .rise @glieli-0f thelever-.2 1lv f maybe regulated to the utmost accu):eey.v 1

The limitof the upward {meramentof V, t

lever 2l is adjusted by means of a set screw 41 carried by bracket 42uprising from the top of the valve' casing.

'I fhe spring 28 serves torequire a greater amount of. air to operatethe choking valve venting a vacuum in the high pressure cy1- inder isconstructed, arranged and operated as follows A bypass port 43. extendsfrom 'end to end of the high pressure cylinder 1,

which pcpt is at all times in open communication w th theintercooler `3t rough a pipe 44. The opposite ends of this bypass port 43 are Cbroughtinto and out of open com munication with the ends of the high pressurecylinder chamber upon opposite sides of' its piston by bypass valves 45.These bypass valvesare similar in construction and one only of them willbe described in detail.r The casing for thelvalve 45 is denotedby 4G andit is inserted from the exterior of the cylinder through `the port 43and has a screw threaded engagement vvith the inner and outer walls ofthe port, The interior of the valve' casing 46 is at alltimes in opencommunication with the port 43 through one or more h oles 47. A centralguide 48 is provided for the stem 49 of the valve 45, which guide isconnected to the inner walls of the casing 46 by a plurality of webs 50.The seat for the valve 45 is located at the inner end of` the casing 46.The valve 45 is' held yieldingly closed by means of a spring 51 which isinterposed between the guide '48 and a cap 52 carried by the stem 4lofthe said valve. A piston 5B is located within the -casi'ng 46 and thevinner side of said piston is at'all -times open to the port 43. Theouter side of the `piston is open at all times to atmosphere in thepresent instance through a pipe 54 which leads to atmosphere, as, forinstance, to the intake 9. A spring 55 is also located within the casing46 in position to' force the piston `53 inwardly against a pressure offrom two to five pounds on the back of the piston from Within thebypassport 43.

The backs of both of the bypass valves 45 are at all times in opencommunication4 with theV bypass port 43 so that they are sub VAjected atall times to the pressure within said port, v iz; inte'rccolcr pressure.It is also to. be observed that the VinterCoOIer pressure is in directcommunication with the `interior of the high pressure cylinder7 throughthe high pressure inlet valvz-zs.

In operation, as the choking controller starts to operate the pressure'in' the intercooler begins to fall. This rreducticui i-n pres; sure in'the lntercooler continues aslong as the cholnngvalve continues toreduce the the intercooler -springs on the outer sides o admission ofair through the intake. The vbypass valves will not be brought intooperation until about one-half of tlliejlcapacty of the compressor isreached or', in Iother words, until the intercoolr pressure falls to apoint any-where between two and five pounds. As the intercoolerpressureis 'in direct communication'with ythe high pressure cylinder and'also is in commumcatlon with the bypass port, the bypass valves aresubstantially balanced,ran increase in the intercooler pressure servingtoshut them and 'a' decrease in ressure serving to open them. When thisintercooler -pressure is reducedi to a suiiiciently low oint, the

the bypass valve pistons will push/the valves open thus bringing bothends of the high pressure cylinder `into oper/ communication.,

' intercooler at each stroke, the intercooler pressure will-risesuiiiciently to shut the bypass valve at one end lof the high pressurecylinder-or at the other end thereof at some part of the piston stroke.'This will .permit the' high pressure cylinder to compress' the amount ofair which may have been con` l tainedv in the cylinder in front of thepiston Aat 4the 'time and discharge it to the finalv receiver. The morethe choking valve is,

shut oli', the -less will be the `amount ofj'ai'r delivered to theintercooler freni the low pressure cylinder at eachstroke untilwhen thechoking valve is shut off entirely only the leakage through the samewill be de.- livered toV the intercooler. In this event, the rise in the`intercooler will be very slow and the opening and shutting of thebypass valves will be intermittent `as they will only'r operate when theintercooler pressure israised to a sufficiently high point to closeeither one or the other of the said valves.

tothe atmosphere as all of the' air-that is taken intothe compressor iscompressed and delivered to the final receiver.

sure cylinder never getsfbelow'atmbspheric pressure, the high pressurecylinder doesnot require any greater number of compressions .120-

pressure cylinder, a low pressure cylinder, aV

choking controller for thelow pressurecylloo' vBy this arrangement, airis never discharged i inder and means operating in. conjuI'xct-ionV withthe choking controller for automatically preventing a vacuum in the hlghpres-4 sure cylinder as the admlsslon ofen.' tothe low pressure'cylinder is reduced by the chok- K ing controller.

,2."In a compound air compressor, a high pressure cylinder, e lowpressure cylinder, a choking controller for the low pressure cylinder,an intercooler and means controlled by intercooler pressure andoperating in conjunction with the choking controller for automaticallypreventing a vacuum in the high pressure cylinder as the admission ofair to the low pressure cylinder is reduced by the choking controller'.1

3. vIn a compound air compressor, a highv pressure cylinder, u lowpressure cylinder, a

choking controller'for the 10W pressure cylinder, 'an intercooler andmeans controlled by intercooler And atmospheric pressure and operatingin conjunction' with the choking" controller" for automaticallypreventing' a Vacuum in the high pressure cylinderes the admission ofair to the low pressure cylinder isV reduced by thechoking controller.

.In :l compound nir compressor, a high pressure cylinder, a. low`pressure'cylindr, Aa

choking controller for the low pressure cylinder, un intereooler, vaby-putss port for the.

high pressure cylinder in 'communication With the intercooler and Valvesin the by pass port, operating in conjunction Wit-h the clickingcontroller, 'arranged to open the by pass port to the opposite sides ofthe piston in the high pressure cylinder as the admise sion of air tothe low pressure cylinder is reduced bythe choking controller, for mutoLmaticully preventing u vacuum in the high pressure cylinder. v

, 5. In a com ound air compressor, a high pressure cylin er, a lowpressure cylinder, u choking controller for the lour pressure cylinder,en intercooler, a by-pass port for the high pressure cylinder inopencommunication with the i'ntereooler, valves inthe by pass port.,operatingin conjunction with the i lchoking controller, arranged to'open the bypass port to'thefopposite sides of the piston in the highpressurecylinder us the admission of air to the low pressure cylinderreduced by the choking controller, for'a'utomatieully preventingaJvacuum in the high` pressure cylinder, and means for placing said valvesunder the influence .of pressure at all times.`

In testimony, that I clainthc foregoing :is my invent-ion, I have signedmy naine in Vpresence of two witnesses, this fourteenth day of April1906.

- W'ILLIAM PRELLVITZ.

Witnesses; WARD RAYMOD, CHAs. C. HAUSUN.

